Cutting, stretching, and twisting



Sept. 16, 1941. R. c. MARTIN 2,256,151

CUTTING, STRETCHING, AND TWISTING Filed Aug. 2, 1940 arrow M,

Patented Sept. 16. 1941.

CUTTING, sran'rcnme, AND 'rwrsrmc Ralph C. Martin, Cuyahoga Falls, Ohio,assignor to Wingi'oot Corporation, Wilmington, Del., a

corporation of Delaware Application August 2, 1940, Serial No. 349,881

2 Claims. (01. 5734) This invention relates to apparatus designed forcutting, twisting and stretching thin sheetv material, such as rubberhydrochloride film. The

.invention includes both the apparatus and the method employedusing theapparatus.

It has previously been suggested that a narrow ribbon of rubberhydrochloride film, for example, a strip several inches wide, becontinuously rolled on the bias with heat and pressure,

and while stretching the film, to produce a thin thread or filament ofcompacted stretched rub- This invention relates to the loose twistingand stretching of a rather narrow strip or strand of rubber hydrochoridefilm. Such a loosely twisted product has different properties from thecompact article of the prior art just described and is particularlydesigned for use in-weaving rugs, tapestries, upholstery, etc. ..Thecrinkling of the thin stretched film which results from twisting causesa reflection of light from the film which is attractive in that it givesthe appearance of great life to the article. The stretching givesdesired strength. The material is inherently waterproof. By weavingfilms which are differently colored by dyes or pigments or metallicpowders, pleasing decorative efiects are produced. a 1

The apparatus of this invention is designed for the production of theloosely twisted strand on a commercial scale. It provides for cuttingthe strips to be twisted from a roll of the film and stretching andtwisting these strips. The apparatus may be easily made by-suitableadaptation of one of the conventional cotton twisters now available onthe market, such as a Saco-Lowell type of twister. The invention will befurther described in connection with the accompanying drawing in whichFig. 1 is a view in perspective of the apparatus of the invention, andFig. 2 is a front view of the same.

. The roll of cast rubber hydrochloride film I from which the twistedstrips are to be formed is supported on any suitable bar 2. The film lis brought from this roll I over the roll which is mounted on the arms 5which are held by the 'spring 6 so. that the roll 4 is continuously heldagainst the roll of film I, regardless of whether the-roll I is large asat the first 01a run, or small as near the end of a run when the film ontheroll I has been almost entirely used. As the film leaves the roll 4,it is split by the knife blades 1 which are supported by the bars 8,which are supported from the bar 5 by hinges and held in position by aspring. The purpose in mounting the knives and the roll 4 on movablebarsis to give flexibility to the machine to facilitate threading filmthrough the machine to start operations.

The drawing shows three knife blades 1 which split the film into fourparts 9. This is illus trative only. Any number of knives may be used.Ordinarily the film will be cut into strips about one inch wide. Thestrips may be as wide as two inches or wider, and as narrow as one-halfinch or narrower. The strips are passed under the roller I0 and thenthrough the ring II which prevents their separating prematurely andripping the film ahead of the knife blades .1. From the ring II, theseparate strips 9 are fed around grooved guides I2 to suitable heatingmeans. Other heating means may be substituted for that here shown whichcomprises the rolls l3, I4 and IS. The rolls" l3 and I4 in the designshown are long rolls extending preferably the width of the machine. Oneor both of these rolls are driven rolls. The short rolls I5 rest on therolls I3 and I4 and are driven by them. Guide means (not shown) keep therolls I5 from migrating to the left .or

right. From the roll I4 the individual strips of film pass over the barIt through the eyes I! to the twisting mechanism.

The twisting mechanism may be of any usual design. As shown, itcomprises the spindles l8 driven by belt-s (not shown) which pass aroundthe pulleys I9. Overthe spindles are the spools 20 which are rotated ata high speed' by the spindles. The bar 2| is mounted so that it movesvertically up and down over the length of the spools as the twisted filmis wound onto the spools. The spools are located within holes in the bar2|. The bar 2| is equipped with the usual rings 22'on which'thetravellers 23 of the usual type circulate in winding the twisted stripson the spools. The equipment indicated by the numerals I'I through 23inclusive may be of a v conventional type and operated in theconventional manner.

In passing from the roll I to the spool, the film is heated andstretched. The most satisfactory place for applying heat is through theroll ll. This roll may, for example, be heated to such a temperaturethat in passing over the roll the tfilm is heated to a temperaturearound 90 to 100 C. The pressure of the roll Ii on the roll ll maintainsthe'rate'of feed of the film over the roll ll. The winding mechanism isso geared that the twisted strip is wound on the spool at a greaterlineal speed than that at which it passes over the roll ll. .It is woundon the spool at a speed at least double that of the surface speed of theroll l4 and may be' wound at a'rate four or five or more times thatofthe surface speed of the roll M. This stretches the heated and thstretch normally takes place just'as the film leaves the roll M. Thefilm is ,kept in a fiat condition from the supply roll- I until itpasses over the bar l6. After itleaves the bar l6, it is twisted by themovement of the traveller in the way that cotton yarn is commonlytwisted. The film is quickly cooled by the air and its temperature islowered to the point where on twisting, the overlapping, contactingplies do not become heat-sealed together. The twist imparted to'the filmmay be about one and one-half to two and one-half I turns per inch to anarrow ribbon of the film which is about one inch'wide and only afraction of a hundredth of aninch. thick. Ordinarily the film suppliedto the apparatus will be about .001 of an inch thick. It may betransparent or colored with a pigment or dye. It may contain astabilizer, such as hexamethylenetetramine.

The bar It may be replaced by a driven roller, and by driving it at agreater surface speed than the roller ll, so that by properly heatingthe film it is stretched in passing between these rollers.

As described in the co-pending application of ing each separate strip offilm and simultanev Gerald D. Mallory, Serial Number 349,644, filed Aug.2, 1940, the device may be used for producing a film which will notuntwist by providingmeans for supplying adhesive or solvent to the filmbefore or during the twisting operation.

The solvent or cement, for example, may be supplied to the film as itpasses over the bar Hi.

This may be accomplished by any usual means, such as an applying rollwhich dips into a bath of liquid adhesive or solvent. Drying meansshould be provided to insure removal of all liquids ously winding it ata speed higher than the speed of travel of the surface of the heatedroller.

2. The method of treating cast rubber hydrochloride film continuouslywhich comprises slitting a sheet of the same into a plurality of strips,

heating each strip and stretching it while preventing it from twistingand then cooling, twisting and winding each strip separately andseparately winding it at a higher rate than that at which it is heatedso that each strip of the heated film is stretched.

RALPH C. MARTIN.

